High FDG activity in focal fat necrosis: a pitfall in interpretation of posttreatment PET/CT in patients with non-Hodgkin lymphoma

  • Raghava Kashyap
  • Eddie Lau
  • Anupkumar George
  • John F. Seymour
  • Stephen Lade
  • Rodney J. Hicks
  • Michael S. HofmanEmail author
Original Article



PET/CT has a major role in lymphoma imaging, but glycolytic activity in inflammatory processes can reduce specificity. In this study we evaluated restaging PET/CT findings in patients with non-Hodgkin lymphoma (NHL) and fat necrosis.


We identified 16 patients from 8,819 restaging FDG PET/CT scans with suspicion of or biopsy-proven fat necrosis on PET/CT.


All patients had NHL and demonstrated focal FDG-avid nodular change on CT with density higher than that of fat but lower than that of soft tissue. Histological confirmation was obtained in eight patients, with high GLUT-1 staining between necrotic tissue and organizing fat necrosis evident. Uptake resolved in four patients, and surveillance was continuing in four without relapse.


Although rare, identification of fat necrosis in patients with a solitary FDG-avid nodule after therapy is important and may lead to the avoidance of unnecessary interventions or treatment. Specific features on CT aid identification, whilst follow-up imaging can be helpful as the metabolic abnormality regresses with time.


PET Non-Hodgkin lymphoma Fat necrosis False positive 



We would like to thank Dr. M. Dickinson, Professor M. Prince and Associate Professor D. Ritchie for contributing cases. Dr. R. Kashyap was supported by Endeavour Awards, a venture of Austraining International in partnership with the Government of Australia.

Conflicts of interest



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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Raghava Kashyap
    • 1
  • Eddie Lau
    • 1
    • 5
  • Anupkumar George
    • 2
  • John F. Seymour
    • 2
    • 4
  • Stephen Lade
    • 3
  • Rodney J. Hicks
    • 1
    • 4
    • 5
  • Michael S. Hofman
    • 1
    • 4
    Email author
  1. 1.Centre for Cancer ImagingPeter MacCallum Cancer CentreMelbourneAustralia
  2. 2.Department of HaematologyPeter MacCallum Cancer CentreMelbourneAustralia
  3. 3.Department of PathologyPeter MacCallum Cancer CentreMelbourneAustralia
  4. 4.Department of MedicineUniversity of MelbourneMelbourneAustralia
  5. 5.Department of RadiologyUniversity of MelbourneMelbourneAustralia

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